The AutoCorrect function on iPhone is an automatic feature that makes spelling corrections made while texting or typing. In most cases, this feature is very helpful and actually helps you type faster. However, the feature can be a nuisance to those who use a lot of abbreviations, as it will correct these "misspellings" and insert words that don't make any sense.
AutoCorrect is enabled by default, but if you're tired of correcting the corrector, here's a simple way to turn it off.
How To Disable AutoCorrect on iPhone
Open your Settings, and then go to General.
Select the Keyboard option, and find the option for Auto-Correction. Simply tap the switch to turn it off.
You can turn the feature back on by flipping the switch back to green.